First, it has a stimulating effect on the
respiratory centers in the brain;
The authors would like to thank the University of Sulaimani for supporting the project and the staff of SHAR Hospital
Respiratory Center in Sulaimani city for technical assistance.
The
respiratory center stimulation results in hyperventilation and excess wash out of carbon dioxide (C[O.sub.2]).
As the duration of breath holding during pranayama is gradually increased by the practice of pranayama so that the
respiratory center is acclimatized to withstand higher and higher carbon-di-oxide concentrations in the alveoli and the blood.
This ultimately triggers the stimulation of the
respiratory center in the brain, which causes the person to awaken briefly to take some quick, deep breaths.
Observation of newborns will reveal that most all of them have irregular respiratory patterns, characterized by periods of rapid breathing followed by brief pauses in respiratory effort, termed "periodic breathing." This is also felt to be due to
respiratory center immaturity but is NOT considered abnormal unless associated with decrease heat rate or color change.
(8, 14) In the present study, improved pulmonary function in luteal phase might be related to high progesterone level which induces hyperventilation by : 1.Direct stimulation of
respiratory center. (15) Respiratory response to progesterone is mediated at a hypothalamic site through an estrogen (E2) dependent progesterone receptor (PR) mediated mechanism requiring RNA and protein synthesis (gene expression).
The blood oxygen saturation decreases during an episode of apnea, which ultimately activates the
respiratory center in the brainstem.
Depression of the
respiratory center such as with anesthetics, sedative (morphine), cerebral trauma or tumors.
Furthermore, practice of Pranayama may lead to alteration in responsiveness of medullary
respiratory centers as well as central and peripheral chemoreceptors increasing respiratory endurance and BHT.
(11,12) Especially infra-tentorial tumors can affect cardiac and
respiratory centers, and lead to sudden death.
Other manifestations reported in the literature include nausea, vomiting, keratoconjunctivitis, blurred vision, photophobia, blepharospasm, and lacrimation.4 In lethal H2S exposure, sulfides act on the
respiratory centers of the brain causing respiratory paralysis.